AfW - suspend apps - API polish

* renamed getPackageSuspended => isPackageSuspended
* does not return false for an error, instead throws
  NameNotFoundException if the package could not be
  found, or if there is an unknown RemoteException,
  wraps it in a RuntimeException and rethrows.

Bug: 27532430
Bug: 22776761
Change-Id: Iee00600089b1c0556a3312b10456826464fa8f9f